Lung cancer is the leading cause of cancer-related deaths in both men and women worldwide. The Center for Disease Control and Prevention (CDC) says it is responsible for more deaths in the United States each year than breast, colon and prostate cancers combined.

(From left to right) Research work by Mudit Vaid, Som Datta Sharma, Santosh Katiyar and Sabarish Ramachandran shows that grape seed proanthocyanidins (GSPs) can inhibit the growth of human small cell lung cancer.

The journal Clinical Cancer Research recently published Katiyar’s findings that suggest the feeding of grape seed proanthocyanidins (GSPs) supplemented with a controlled diet inhibits the growth of lung cancer xenograft in mouse models. The research also shows that GSPs have the ability to kill lung tumor cells in vitro, but that they do not inhibit the growth or kill normal cells.

“This is a new and innovative finding because it’s the first time it has been reported that natural phytochemicals from grape seeds have the ability to inhibit the growth of lung cancer cells in vitro and in vivo preclinical mouse model,” Katiyar says. “It accomplishes this, but does not adversely affect the growth of normal bronchial epithelial cells. We conducted a study in vitro in 10 lung-cancer cell lines and also in animal models, and it looks very effective.

“The findings open a new area to further pursue whether or not it has an anti-carcinogenic effect against lung cancer.”

What exactly are proanthocyanidins? 
Proanthocyanidins are key to the research, and there is little doubt of the powerful antioxidant properties of the natural chemical. Research has confirmed that they are 50 times more effective than vitamin E and 20 times more powerful than vitamin C.

Proanthocyanidins are found in high concentrations in cranberries, grape skins, grape seeds, pine bark, lemon tree bark and hazelnut tree leaves. The two most common and richest known sources are grape-seed extract and pine-bark extract.

Research shows that grape-seed extract is the best choice because it yields a 10 percent higher concentration of proanthocyanidins and contains a specific proanthocyanidin with a higher degree of potency.

GSPs are readily available as an extract of grape seeds. For his study, Katiyar treated 10 different lung-cancer cell lines with GSPs and then fed GSPs to animal models as a supplement with their routine diet.

“Lung cancer cells spread very fast, but the GSPs treatment inhibits their growth,” he says. “My idea was if somebody consumed grape seed proanthocyanidins as a dietary supplement, then it might prevent lung cancer.”

Current treatments limited
Small cell and non-small cell lung cancer (NSCLC) account for 90 percent of all lung cancers. NSCLC represents approximately 80 percent of all types of lung cancer and includes squamous cell carcinomas, adenocarcinomas and large cell carcinomas.

The current treatment strategies for advanced lung cancer include surgical resection, radiation, chemotherapy and photodynamic therapy. The cancer already has spread beyond localized disease at the time of diagnosis in almost two-thirds of cases, limiting therapeutic options.

Katiyar has spent the past 18 years studying how the phytochemicals we consume in our daily diet can be used to prevent skin cancers. He believes the research findings for grape seed could lead to development of more effective chemo-preventive and chemo-therapeutic agents that target the molecules associated with tumor-cell proliferation.

“I’m very much encouraged with what this research shows,” he says. “This preclinical study suggests that the regular consumption of GSP-supplemented diet should have strong translational relevance in terms of prevention and treatment of lung-cancer risk in human patients. Further studies are needed to establish GSPs as a pharmacologically safe agent and its use in future practice of medicine.”